SMT devices at home
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A little off topic, but I'm not connected with a better group to ask. A
BS2 will probably drive this project.
I've been challenged by a fellow model railroader to attach wire
connections to a very tiny White LED designed for Surface Mounting (SMT).
The intent is to get #30 wires (the kind used for wire wrapping) soldered
to the back side so as not to increase the effective diameter.
Conventional pigtailed White LEDs are much too large for our application.
Looking for advice before I mess up these pricey little white SMT LEDs. I
do have a Weller solder station and am fluent with it but the smallest SMT
items that I have worked with are multi-leg PICs using conventional
techniques.
Thank You
Wayne Roderick P.E. (EE, ret)
CEO, Teton Short Line, (NMRA life-1721)
e-mail tetonsl@i... Pocatello Idaho, USA
http://www.ida.net/users/tetonsl/railroad
Note new URL- /biz/ becomes /users/
BS2 will probably drive this project.
I've been challenged by a fellow model railroader to attach wire
connections to a very tiny White LED designed for Surface Mounting (SMT).
The intent is to get #30 wires (the kind used for wire wrapping) soldered
to the back side so as not to increase the effective diameter.
Conventional pigtailed White LEDs are much too large for our application.
Looking for advice before I mess up these pricey little white SMT LEDs. I
do have a Weller solder station and am fluent with it but the smallest SMT
items that I have worked with are multi-leg PICs using conventional
techniques.
Thank You
Wayne Roderick P.E. (EE, ret)
CEO, Teton Short Line, (NMRA life-1721)
e-mail tetonsl@i... Pocatello Idaho, USA
http://www.ida.net/users/tetonsl/railroad
Note new URL- /biz/ becomes /users/
Comments
I've had quite a bit of experience with surface mount components. I've
found that you can attach SMT down to "0805" packages using standard
soldering techniques. Of course you must use a fairly small tip on your
iron. I usually use a lighted magnifier and small diameter solder. It will
be important to find a way to hold the LEDs steady. I find that hemostats
are great for this. You don't want to sqeeze it until the handles click
though. I put a rubber band around the handles to create a "gentle" grip
then I clamp the hemostat in a small vise like a Panavise. Hope this helps.
At 10:40 PM 11/09/2000 -0700, you wrote:
>A little off topic, but I'm not connected with a better group to ask. A
>BS2 will probably drive this project.
>
>I've been challenged by a fellow model railroader to attach wire
>connections to a very tiny White LED designed for Surface Mounting (SMT).
>The intent is to get #30 wires (the kind used for wire wrapping) soldered
>to the back side so as not to increase the effective diameter.
>Conventional pigtailed White LEDs are much too large for our application.
>
>Looking for advice before I mess up these pricey little white SMT LEDs. I
>do have a Weller solder station and am fluent with it but the smallest SMT
>items that I have worked with are multi-leg PICs using conventional
>techniques.
>
>Thank You
>
>
>Wayne Roderick P.E. (EE, ret)
>CEO, Teton Short Line, (NMRA life-1721)
>e-mail tetonsl@i... Pocatello Idaho, USA
>http://www.ida.net/users/tetonsl/railroad
>Note new URL- /biz/ becomes /users/
>
>
>
>
>
___________________________________________________________________
_/_/_/_/ _/_/_/ _/_/_/ Lee Harker
_/ _/ _/ Electronic Services
_/_/_/ _/_/ _/ _/_/ 258 Metals Development
_/ _/ _/ _/ Ames Laboratory / ISU
_/_/_/_/ _/_/_/ _/_/_/ Ames, Iowa 50011
ENGINEERING SERVICES GROUP Phone: (515) 294-7906
AMES LABORATORY Fax: (515) 294-0568
IOWA STATE UNIVERSITY E-mail harker@a...
___________________________________________________________________
Thanks for the hands on advice. The only SMTs I've dealt with are the
PICs that came with the DCC decoder kits (no longer available) by Jim
Scorse and 200 1/16 watt resistors that I epoxied to the HO axles for
occupancy detection. The PICs are relatively "large" and the "cold"
conductive epoxy is forgiving. I was spooked by "tiny and hot" at the same
time.
Found some good info at:
http://www.google.com/search?q=cache:fstewart.ne.mediaone.net/DaEtiCsuiSleig
SmtNews.shtml+SMT+repair+solder&hl=en
Looks like the hot air & paste solder is worth looking into too.
Wayne
At 09:12 AM 11/13/00 -0600, you wrote:
>Wayne,
>I've had quite a bit of experience with surface mount components. I've
>found that you can attach SMT down to "0805" packages using standard
>soldering techniques. Of course you must use a fairly small tip on your
>iron. I usually use a lighted magnifier and small diameter solder. It will
>be important to find a way to hold the LEDs steady. I find that hemostats
>are great for this. You don't want to sqeeze it until the handles click
>though. I put a rubber band around the handles to create a "gentle" grip
>then I clamp the hemostat in a small vise like a Panavise. Hope this helps.
>
>
>
>At 10:40 PM 11/09/2000 -0700, you wrote:
>>A little off topic, but I'm not connected with a better group to ask. A
>>BS2 will probably drive this project.
>>
>>I've been challenged by a fellow model railroader to attach wire
>>connections to a very tiny White LED designed for Surface Mounting (SMT).
>>The intent is to get #30 wires (the kind used for wire wrapping) soldered
>>to the back side so as not to increase the effective diameter.
>>Conventional pigtailed White LEDs are much too large for our application.
>>
>>Looking for advice before I mess up these pricey little white SMT LEDs. I
>>do have a Weller solder station and am fluent with it but the smallest SMT
>>items that I have worked with are multi-leg PICs using conventional
>>techniques.
>>
>>Thank You
>>
>>
>>Wayne Roderick P.E. (EE, ret)
>>CEO, Teton Short Line, (NMRA life-1721)
>>e-mail tetonsl@i... Pocatello Idaho, USA
>>http://www.ida.net/users/tetonsl/railroad
>>Note new URL- /biz/ becomes /users/
>>
>>
>>
>>
>>
>
>___________________________________________________________________
>
> _/_/_/_/ _/_/_/ _/_/_/ Lee Harker
> _/ _/ _/ Electronic Services
> _/_/_/ _/_/ _/ _/_/ 258 Metals Development
> _/ _/ _/ _/ Ames Laboratory / ISU
> _/_/_/_/ _/_/_/ _/_/_/ Ames, Iowa 50011
>
> ENGINEERING SERVICES GROUP Phone: (515) 294-7906
> AMES LABORATORY Fax: (515) 294-0568
> IOWA STATE UNIVERSITY E-mail harker@a...
>___________________________________________________________________
>
>
>
>
Wayne Roderick P.E. (EE, ret)
CEO, Teton Short Line, (NMRA life-1721)
e-mail tetonsl@i... Pocatello Idaho, USA
http://www.ida.net/users/tetonsl/railroad
Note new URL- /biz/ becomes /users/
What's wrong with conductive epoxy? Apparently you used it before. At one
time, my company built hybrid circuits, mounting many surface parts with
conductive epoxy.
Ray McArthur
Original Message
From: Wayne Roderick <tetonsl@i...>
To: <basicstamps@egroups.com>
Sent: Monday, November 13, 2000 5:29 PM
Subject: Re: [noparse][[/noparse]basicstamps] SMT devices at home
> Lee:
>
> Thanks for the hands on advice. The only SMTs I've dealt with are the
> PICs that came with the DCC decoder kits (no longer available) by Jim
> Scorse and 200 1/16 watt resistors that I epoxied to the HO axles for
> occupancy detection. The PICs are relatively "large" and the "cold"
> conductive epoxy is forgiving. I was spooked by "tiny and hot" at the
same
> time.
>
> Found some good info at:
>
http://www.google.com/search?q=cache:fstewart.ne.mediaone.net/DaEtiCsuiSleig
> SmtNews.shtml+SMT+repair+solder&hl=en
>
> Looks like the hot air & paste solder is worth looking into too.
> Wayne
>
>
>
>
> At 09:12 AM 11/13/00 -0600, you wrote:
> >Wayne,
> >I've had quite a bit of experience with surface mount components. I've
> >found that you can attach SMT down to "0805" packages using standard
> >soldering techniques. Of course you must use a fairly small tip on your
> >iron. I usually use a lighted magnifier and small diameter solder. It
will
> >be important to find a way to hold the LEDs steady. I find that hemostats
> >are great for this. You don't want to sqeeze it until the handles click
> >though. I put a rubber band around the handles to create a "gentle" grip
> >then I clamp the hemostat in a small vise like a Panavise. Hope this
helps.
> >
> >
> >
> >At 10:40 PM 11/09/2000 -0700, you wrote:
> >>A little off topic, but I'm not connected with a better group to ask. A
> >>BS2 will probably drive this project.
> >>
> >>I've been challenged by a fellow model railroader to attach wire
> >>connections to a very tiny White LED designed for Surface Mounting
(SMT).
> >>The intent is to get #30 wires (the kind used for wire wrapping)
soldered
> >>to the back side so as not to increase the effective diameter.
> >>Conventional pigtailed White LEDs are much too large for our
application.
> >>
> >>Looking for advice before I mess up these pricey little white SMT LEDs.
I
> >>do have a Weller solder station and am fluent with it but the smallest
SMT
> >>items that I have worked with are multi-leg PICs using conventional
> >>techniques.
> >>
> >>Thank You
> >>
> >>
> >>Wayne Roderick P.E. (EE, ret)
> >>CEO, Teton Short Line, (NMRA life-1721)
> >>e-mail tetonsl@i... Pocatello Idaho, USA
> >>http://www.ida.net/users/tetonsl/railroad
> >>Note new URL- /biz/ becomes /users/
> >>
DIP-8 adapter boards. I use them (for example) with the LTC2400 part. These
let you solder the SOIC part onto the adapter, then you plug the adapter
into a regular DIP-8 socket. Good for prototyping and such. If interested
please contact me off-list. Thanks!
Steve
Steve Roberts: sroberts@s...
>Wayne:
>What's wrong with conductive epoxy? Apparently you used it before. At one
>time, my company built hybrid circuits, mounting many surface parts with
>conductive epoxy.
>
>Ray McArthur
Good question- I guess I was looking for strength so the LED could be
handled by its new leads. The idea is to mount it in an HO scale (1/87)
signal and retain the scale as close as possible. sub-miniature Red, yel &
Grn LEDs are economical and readily avaiable with leads. As far as I
know, the only option in white is SMT. A fourth color is frequently used
in railroad signaling and its called LUNAR, a bluish white. The white LEDs
are near perfect.
Wayne
Wayne Roderick P.E. (EE, ret)
CEO, Teton Short Line, (NMRA life-1721)
e-mail tetonsl@i... Pocatello Idaho, USA
http://www.ida.net/users/tetonsl/railroad
Note new URL- /biz/ becomes /users/
My Digikey catalog lists what they call "Bright-White" Leds on page 646.
They have T-1 and T-1-3/4 with leads, ($3 ea). Would these be applicable to
your project?
Regards,
Ray McArthur
Original Message
From: Wayne Roderick <tetonsl@i...>
To: <basicstamps@egroups.com>
Sent: Monday, November 13, 2000 10:26 PM
Subject: Re: [noparse][[/noparse]basicstamps] SMT devices at home
> At 07:20 PM 11/13/00 -0500, you wrote:
.........>As far as I
> know, the only option in white is SMT. A fourth color is frequently used
> in railroad signaling and its called LUNAR, a bluish white. The white
LEDs
> are near perfect.